Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.

User Name:

Password

Please enter a password for your user account. Note that passwords are case-sensitive.

Password:

Confirm Password:

Email Address

Please enter a valid email address for yourself.

Email Address:

Insurance

Please select your insurance company (Optional)

Log-in

User Name

Remember Me?

Password

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Additional Options

Miscellaneous Options

Automatically parse links in text

Automatically embed media (requires automatic parsing of links in text to be on).

patterntek.com is the website i believe... they actually dip whatever u have in CF. It looks great and I am actually wanting them to do my car.

06-26-2009 11:04 AM

OneMoreTime

Quote:

Originally Posted by mxa055

Hi there,
I know this is a buried thread but wanted to ask a relevant question.

If you manufacture a carbon fiber hood with bagging process using a mold from the current hood, first how are you supposed to form the bottom side of the hood since the mold only takes care of the upper side and secondly how can you attach hinges and supporting frame to the molded hood?

Also how many layers do you think are needed?

Actually it will take 2 molds..one for the hood itself and a mold for the underside structure..then the two are mated and bonded..the attachment points are reinforced and in the underside structure to provide points to attach the hinges and hood latch mechanism..

At least that is the way I would go about it..

Sam

06-26-2009 01:44 AM

mxa055

Hi there,
I know this is a buried thread but wanted to ask a relevant question.

If you manufacture a carbon fiber hood with bagging process using a mold from the current hood, first how are you supposed to form the bottom side of the hood since the mold only takes care of the upper side and secondly how can you attach hinges and supporting frame to the molded hood?

Also how many layers do you think are needed?

01-11-2005 10:51 AM

blndweasel

question from hotrodders member... posted here because it has useful info on wet layp composite work.

100% wet layup. No vacuum bags here. I sanded the tank down with 150 grit, sprayed it black with rustoleum rattle can paint, roughed up the surface just a little bit more, then layed down a thin layer of thin epoxy resin, let the resin set up (until it reached the latter end of its pot life) then just layed the fiber sheet on top, and the epoxy below will act like a glue. You can basically let this fiber dry for up to an hour or more, getting the epoxy "glue" underneath to set up real good. At that point, you can laminate the outer surface with more THIN epoxy resin. On my gas tank, since I had blending patterns of carbon fiber and carbon/kevlar, it took me over five or six laminates to get the surface smooth. I would recommend keeping it to one type of fiber though, and absolutely no more than three laminates on top.

The reason behind using thin epoxy resin is because of what I mentioned with the bubbles on the firewall. I used thick epoxy resin here, and when this stuff is in the pot mixed up it has the consistency of molasses. This is why bubbles get trapped in it so easily. The thin epoxy resin you have to let set up a little bit more in the pot before you apply it so it doesn't get all runny, but it allows bubbles to work their way out while its drying up.

A simple way of manipulating wet epoxy on the surface of the part is to use a clean, unused bondo scraper as sold at auto parts stores, the flexible plastic kind. You can use this like a spatula to manipulate the wet epoxy, and it shouldn't get caught on the fiber underneath.

You should get a feel for how much you can stretch a single piece of fabric before it begins to distort the pattern. I learned it through trial and error. The gas tank and body panels I did are relatively simple patterns, topologically. The firewall in my vette was much more complicated. I used four pieces of fabric to do this, namely, I split the entire project in half (bisected it) down the middle, and on both the left and right sides I first layed up a piece on the top half, making sure to cover the convolutions and indentations in the firewall upper half. Then I used a second piece on both the left and right sides to cover the large flat areas, making sure to keep the pattern clean because this is the most noticable aesthetic part of the firewall. Then, after cleaning up the ragged edges (some of this was done before the bottom pieces of fabric were layed up), using a dremel tool and sanding drums, also a structured tungsten carbide cutting bit (these things are worth the $15, they cut through dried carbon fiber like a hot knife through butter), I cut out excess material and did the final lamination.

In my case, I used thick epoxy resin on the firewall because I wanted as little seepage and running as possible. I think in hindsight this was a mistake, because when I went to polish this surface, tiny air bubbles existed right below the surface. Thin epoxy resin is harder to work with, produces thinner layers of laminate, but overall retains a more appealing look when it's said and done.

Good luck and let me know if you have any more questions.

Other info... Only sand between laminate layers if you've waited more than 2 hours since the last layer, or if you notice "clouding" in the resin (a result of moisture condensing on the surface of the drying epoxy)

Polish with increasing fineties of sandpaper, all the way up to 1500 or even 2000 grit, then polish with 3M rubbing compound, and finish with 3M finishing compound.

Apply UV sealant if you wish, but I prefer the raw epoxy surface. If you scratch it or leave a mark, just polish it again! Besides I'm not sure how well paint / clearcoat will apply to a polished epoxy surface.

I'm going to post this to hotrodders to hopefully avoid answering the same sorts of questions multiple times...

I'm doing carbon/wood/carbon interior panels for my Corvette. http://corvetteforum.net/classics/gr...corvette15.htm I'm not nearly as good at it as the guys in our shop but have found it is much easier to get a good finish with vacuum bagging than without, as the wet layups have lots of pin-holes in the corners of the fabric weave. It helps if you put a layer of resin with cavasil mixed in to thicken it into the mold first.

You can also put a top layer of very fine weave fiberglass cloth on, as it will disapear when wetted out. You can do this either in the original laminate or as a second bond if you use a peal ply. If you sand the surface for the second bond you will never get all the white resin dust out of the pinholes, and this in turn helps propogate new pin holes in the next layer.

-Greg

12-15-2004 04:29 PM

mmartin1872

another good site is rcuniverse.com go to the airplane section of the forum buttons... and scroll down till you find composite fabrication and repair... whole bunch of good info there and most of those people like to save their pennies so they have insight on making ovens, vacuum bagging tools out of old fridges, and different fabrication techniques for making light pieces.. tons of free info there

12-15-2004 11:33 AM

AmonTobin

I've never laid any composites, but plan on doing something soon. I have found this project aircraft place that sells a "composites practice kit" which might be good for picking up some technique before ruining your precious carbon fiber:

I finished uploading some fiber pics to my gallery. these are wet-layup ontop of fiberglass and painted metal. the epoxy resin will bond to just about any gripping surface, such as lightly sanded painted metal (in the case of the gas tank). It takes a ridiculous amount of wet sanding to get the final product to look good, and my process does not account for UV-protection on the pieces (epoxy resin will yellow over time with exposure to UV). Nonetheless, I get many compliments on my bike, which was my "experimental" phase of carbon / composite wet layup study. Overall I'm happy with the outcome, even before polishing the engine bay the results are spectacular. I can't wait to set all my polished aluminum parts against that backdrop when the motor goes in. If you have any questions feel free to email me.

Cheers

the blonde weasel

i'll just attach one photo for those unfortunate souls still using dialup. high-res versions available in my gallery.

11-12-2004 11:23 PM

willys36@aol.com

Re: How can I make carbon fiber

Quote:

Originally posted by Rain_dog Is there a school one can attend to learn how to make carbon fiber components?

jay

Yes, read my post two above this one. These guys may be a waste of time for experts like lowdown99 but for a novice they seem to be a great resource. Videos, hands-on schools, and all the components that are sure to be compatible.

11-12-2004 10:33 PM

Rain_dog

How can I make carbon fiber

Is there a school one can attend to learn how to make carbon fiber components?

jay

11-12-2004 06:48 PM

lowdown99

select products is where to go if you have a problem like too much money to blow , or cant do a little searching for info on the net. you can purchase th esame exact items at half the cost at shopmaninc.com, as for speaker rings and such , if you cant rout out a set yourself , you probably shoulnt be attempting this kind of stuff anyway, you'll probably end up bonded to your project for life . as for the autoclave and such , unless you are building structural parts and such all this is just appearance stuff which doesnt need the bagging and autoclave.use senseand you will do fine

This thread has more than 15 replies.
Click here to review the whole thread.